Zalasiewicz is one geologist who has given some thought to what will remain in 10,000 years. Certainly some record of cities, plastics and the millions of fossil-fuel wells and mines will persist as what he calls technofossils. The concentrations of carbon dioxide in the atmosphere could still be out of whack from the emissions resulting from the burning of all those fossil fuels in just the last few decades. In a million years, barring profound shifts, the climate should have returned to its natural rhythms but any cities buried in sediment by rising seas should still be preserved, along with those signs of anthroturbation, human-induced disturbances underground, like the plutons from underground explosions of nuclear bombs. Those are good for 10 million even 100 million years, or until plate tectonics lifts them back to the surface and exposes those strata to the rain that will, ever so slowly, erode these signs away. For certain, nothing made by contemporary humanity will be left at the surface that far in the future, even stone edifices like the pyramids or Mount Rushmore will be wiped away, though the fine imprints of plastic objects, like say a vinyl record, may be legible—and even perhaps listenable—in the rock like the fronds of a fern.

Ten thousand years is all that separates today’s people from those who lived at Catalhöyük in Turkey, a city whose mud-brick homes had doors in the roofs. The inhabitants were seemingly obsessed with leopards, slept on their own ancestors’ graves and occasionally kept the skulls as mementoes. In the far future will anyone even understand the binary code and English scrawlings in the Roman alphabet in which the very idea of the Anthropocene is recorded? The Rosetta stone was required to unlock the mysteries of hieroglyphics from a mere 5,000 years ago and the world is no closer to understanding the hash marks left by ancient hominins hundreds of thousands of years ago. One million years ago, Homo sapiens did not exist and our hominin ancestors stalked the savannas of Africa and perhaps not much else, the human population explosion still far in the future.